Most of the automatic pet feeders of past inventions were on a large scale assuming cats and dogs for their beneficiaries. Timers or sensors were used to trigger the switch to activate a driving block of motors on and off to drive the feeding mechanism. (See, for example, the following Japanese patent publications: Nos. 55-34080, 55-54831, 55-37141, 55-37142, 58-56625, 59-66822, 59-95831, 61-152222.)
The driving block requires not only the motor but also gears, pulleys, belts, brakes, etc. Subsequently, the cost increases as does the number of the elements, and the system demands the mechanism to become large and complicated. For this reason, the automatic pet feeders in the past have not been widely used in the ordinary household.
In the case of small pets like fish and unlike the other kinds of pets, the difficulty of moving the water tank made it hard to leave them in the hands of the others. During a keepers' long absence, there may be such inconveniences as having to arrange for neighbors or friends to come to the actual site and feed the small pet.
Also, pet keepers who keep busy schedules during the day, or who work on an irregular shift cannot bother their family or friends and feeding became very irregular. Moreover, individuals who want to start a hobby of keeping small pets, such as fish, are discouraged to do so, due to such hassles and inconveniences.
This invention tries to solve such problems and offers a low-cost automatic pet feeder which can be easily handled in the ordinary household.